In Promise, there is the provision that we can assign the part number to symbols at once. Sometimes after copying the project you need to change the only part number of symbols; you can achieve that by using BOM explorer.
1) Open BOM Explorer
2) Consider one sample symbol Coil Relay Device ID: - CR101 which has no Part Number and drag the part number 0105720000 to that CR101 symbol.
3) EDC pop-out, Click Yes
4) Result: - Device ID CR101 assigned with part number.